In recent years, it is known that an examination based on a chemiluminescence method has very high sensitivity and has high reliability for the measurement, so that such an examination is not limited to an immunological examination but used in a wide field. For example, in order to measure an amount of amplified nucleic acids, a method for detecting an amplified product (RNAs) by measuring the strength of chemiluminescence with the use of an acridinium ester-labeled single strand DNA probe complementary to the amplified RNA strands is known. This method is used for detection of amplified RNAs (HPA measurement principle), which includes hybridizing a probe with a sample after completion of the amplification to form a double strand RNA-DNA hybrid, then deactivating acridinium ester of the unreacted probe that has not formed the hybrid through hydrolysis, in which acridinium ester of the probe that has formed the hybrid is protected and thus does not undergo the hydrolysis so that the chemiluminescence property is maintained, and measuring the strength of this chemiluminescence.
Accordingly, it is required to provide a more efficient and reliable autoanalyzer which is suitable also in the field in which a nucleic acid is handled.
However, there is a problem in that such a conventional autoanalyzer may require a complicated structure and control for carrying out light shielding because, when the autoanalyzer carries out measurement by guiding light between the above-mentioned reaction vessel and a PMT (photomultiplier tube), it is necessary to open and close a shutter provided to the PMT for protecting the PMT against noise light by driving its own motor for driving the shutter before bringing the reaction vessel into a light shielding state, and it is also necessary to guide the light along with the PMT while strictly maintaining the light shielding of the reaction vessel.
In order to carry out measurement, liquids targeted for measurement are transferred and dispensed into the reaction vessels for exclusive use in photometry provided in the vicinity of the PMT, or the vessels themselves are transferred to the location for measurement in the vicinity of the PMT one by one. Accordingly, in order to carry out measurement, the time is required to transfer the liquid or reaction vessel for every measurement. Therefore, when there are a large number of the reaction vessels to be measured, there is a problem in that the treatment time may increase.
In particular, when measurement of chemiluminescence is carried out by a CLIA assay, there is a problem in that a reliable measurement may not be carried out. This is because it is necessary to dispense a trigger reagent into the reaction vessels provided at the location for measurement in the vicinity of the PMT, by which the dispensed liquid is scattered to the PMT provided in the vicinity of the reaction vessels and the shutter for protecting the PMT against noise light, with the result that the PMT is contaminated and light reception is inhibited.